INTRODUCTION– Final restoration of endodontically treated teeth often requires a post and core. Space for the post is obtained by removing a predetermined amount of root canal filling material and then preparing the canal with reamers or drills to the desired form and shape. AIM & OBJECTIVE– 1. To compare the fracture resistance of endodontically treated teeth restored with glass fiber post, prefabricated metallic post, cast metallic post core and prepared teeth.2. To compare the site of fracture of endodontically treated teeth restored with glass fiber post, prefabricated metallic post, cast metallic post core and prepared teeth METHODOLOGY– A total of 40 samples were prepared to evaluate the fracture resistance and site of fracture of endodontically treated teeth restored with glass fiber post, prefabricated metallic post, cast metallic post core and prepared teeth. A total of 40 extracted human mandibular 1st premolar teeth were used within 3 months following extraction. RESULT– SIMULATION 1– On the basis of above observations the following order of fracture load in different groups was observed: Group III > Group IV > Group I ~ Group II SIMULATION 2– On the basis of above observations the following order of fracture load in different groups was observed: Group IV > Group III > Group I > Group II CONCLUSION– 1.So, from the result of this study, it was concluded that under conditions of vertical loading, the fracture load of teeth restored with the cast metallic post–cores was greatest among the groups and under the condition of oblique loading, the fracture load of teeth restored with pre–fabricated metallic posts was significantly smaller than that in other groups.2.The combination of a fiber post and composite resin core with a full cast crown is the most protective method for maintaining tooth structure.3.All the fractures in the specimen samples, irrespective of the nature/ presence of post took place at cervical region.